1. Field of the Invention
This invention relates to a rotary vane-type engine with a rotatable rotor having radial slots in which working vanes are guided for radial displacement therein, the vanes having radially outwardly directed end surfaces for abutting engagement with the inner contour of a cam ring surrounding the rotor, the vanes subdividing the chamber formed between the cam ring and the rotor into working spaces, with side plates being provided which abut against the front surfaces of rotor and cam ring and include control ports for the supply and discharge of fluid, and with a throttle channel provided at the end of the control port extending in the rotor circumferential direction, the throttle channel permitting communication between the working spaces arranged on either side of the throttle channel.
2. Description of the Prior Art
From U.S. Pat. No. 2,588,430, a rotary blade pump is known which includes a rotatable rotor having radial slots therein. The slots receive radially displaceable working blades having radially outwardly directed end surfaces adapted for abutting engagement with the inner contour of a cam ring surrounding the rotor. The working blades subdivide the chamber formed between the rotor and the cam ring into working spaces. The front surfaces of rotor and cam ring are in contact with side plates in which control ports for the supply and discharge of fluid are provided. The fluid discharge ports are provided with a throttle notch at one of their ends extending in the rotor circumferential direction, the length of the notch extending in the rotor circumferential direction being greater than the width of the working blades.
If, during operation of the rotary blade pump, a working blade overtravels the throttle notch, the working spaces on either side of the working blade are in communication with each other through the throttle notch so that the low-pressure working space is pressurized to the pressure prevailing in the high-pressure working space.
This pressurization occurs during a very short period within which the distance covered by the working blade in the rotor circumferential direction is shorter than the amount of width of the working blade. It is within this short period within which the low-pressure condition changes to a high-pressure condition that peak pressures and compressional vibrations occur which cause disturbing noise.